The Acute Respiratory Distress Syndrome (ARDS) Clinical Network was established as a contract program in 1994 following a national competition. The network has ten clinical centers (composed of 24 hospitals) and one clinical coordinating center. The network was established to hasten the development of effective therapy for ARDS by evaluating new treatments and management practices in a rigorous, controlled setting. The Steering Committee, comprised of network investigators, selects and develops protocols that are reviewed for scientific merit by an independent Protocol Review Committee. Once approved by this committee, the Data Safety and Monitoring Board, that is composed of experts in critical care and pulmonary medicine, statistics, and ethics, advises the institute on conduct of the study, including data quality and analysis, recruitment or other issues faced by the investigators, and human safety concerns. An electronic data collection system and a web site for network investigators were established by the coordinating center to facilitate ease of data management and communication between the hospitals that comprise the ARDS Network. Data quality is carefully monitored at technical site visits and reviews. By conducting careful, controlled clinical trials, the network offers the opportunity for systematic evaluation of new therapies and management practices and also offers a model for clinical investigation in complex studies. As of Summer 2001, the network has completed 3 protocols and is conducting 3 others. An additional 10 centers were added in the fall of 2000 to assist in a study comparing the pulmonary artery catheter vs central venous catheter, and two fluid management strategies in treating acute lung injury and ARDS. Completed studies are: Respiratory Management in Acute Lung Injury and ARDS; Ketoconazaole in Acute Lung Injury and ARDS; and Lisofylline in Acute Lung Injury and ARDS. Studies in progess are: The Late Steroid Rescue Study; Assessment of Low Tidal Volume and Elevated End-Expiratory Volume to Obviate Lung Injury, and The Pulmonary Artery Catheter/Fluid Management Study in Acute Lung Injury and ARDS.